There has been a growing trend moving away from conventional tillage ideas in the growing of row crops and toward minimum tillage methods. This has been due in part to increases in labor, fuel and machinery costs and also because it has been determined that certain minimum tillage systems can reduce the aforementioned costs without reducing yields. In one such minimum tillage system, a ridge is formed and the row crop is planted in such ridge. The purpose of planting on a ridge is because during the winter, in a properly ridged field, trash and residue will fall off of the ridges and collect between the rows. The ridge remains high and clear, so, when spring comes, the ridge warms up first, while temperatures remain 10.degree.-12.degree. F. cooler under the cover of residue between the ridges. Consequently, the crop can be planted on the ridge much earlier than would be possible in cooler soil. Since the soil is not worked before the planting when using the aforementioned ridge type minimum tilling system, the moisture stays where it is needed. This is particularly important in dry years. Then, when a planter is used, it sweeps off the top of the ridge and makes a moist, mellow seed bed for quick germination and fast starts for the row crop.
Another advantage of using ridges in a minimum tillage system is for weed control. As a sweep is used to clean off the top of the ridge, residue and weed seeds are pushed into the valleys inbetween the rows where they are easily controlled, either by cultivation or with a herbicide.
Soil compaction is not a problem with a ridging system because the natural weathering process of freezing and thawing, wetting and drying, are constantly at work during the winter and spring loosening up the soil. The result is an ideal seed bed.
A further advantage of the system when the crop residues are left on the top, the organic matter therein breaks down much more rapidly into beneficial soil components. Additionally, the residue helps prevent wind and water erosion and reduce moisture loss in the soil due to evaporation. Also, the residue between the rows keeps the soil cooler, which means that the weed seeds that are between the rows get a slower start than the crops which are on the warmer ridges.
The prior art method of developing the aforementioned ridges for minimum tillage planting on such ridges is to use pairs of discs attached between the rows of cultivators. For example, a typical sweep for cutting weeds just below the soil would be followed up by such a set of discs which each have a pitch angle thereon whereby the fronts of such discs are close together and the rear portions of the discs are spaced further apart, and whereby each of the discs will gather dirt and throw such dirt outwardly, thereby forming a trench just behind such sweep and ridges to each side thereof, where the row crops are growing.
One of the problems with using pairs of discs to form the ridges is that a consistent ridge is difficult to form if the field has rocks or other obstacles therein which interfere with proper functioning of such discs systems. Another problem with discs systems is that they are substantially fixed, which is no problem if the rows are straight, but becomes a problem when the rows are not straight because if the sweep is disposed directly in the center of the row during a turn, then the ridge forming discs will be to one side or the other thereby forming a higher ridge on one side and a lower one on the other, or perhaps even cutting off some of the growing crops in the rows.
Consequently, there is a need for a ridge forming apparatus for attachment to cultivators which will overcome the aforementioned deficiencies in the prior art.